Melting Antarctic Ice Shelves. Published scientific studies show that
the West Antarctic Ice Sheet is melting, with possible consequences for future
generations. Ice sheets are glaciers covering large areas of a continent and
are often referred to as "continental glaciers". All glaciers tend
to flow like rivers of ice. Ice sheets flowing into the sea are slowed by ice
shelves, which are extensions of the ice sheets made of floating ice. The
breakup of ice shelves may allow an ice sheet to flow faster into the sea,
possibly leading to its ultimate breakup. The problem is, although floating ice
doesn't raise sea levels when it melts, the ice entering the sea from ice
sheets does, because it is ice that was originally grounded.

A recent study (Science346:1227 (2014)) finds evidence that
the diminishing of the West Antarctic Ice Sheet is being abetted by warmer
water flowing up under Antarctic ice shelves. One component of the two that
constitute this water, the Circumpolar Deep Water, has warmed all around the
Antarctic continent. Since it has recently be shown that by far most of
"global warming" is in the oceans, this situation may accelerate and enhance
rising sea levels.

Where Does Hawaiian Lava Come From? A long-lived controversy in
geophysics is the origin of volcanism at so-called "hot spots", such as the
one under the Hawaiian Islands. There are many others, including the one under
Yellowstone National Park. One view believes these hot spots are due to magma
rising from deep within the Earth - from the mantle-core boundary. Others think
the volcanism is from a thin layer of the upper mantle just below the Earth's
crust (of which the continents and sea floor are made) that appears to consist
of "partial melting": analogous to water in a bucket of sand where the water
is the magma and the sand the unmelted minerals. This layer is called the
asthenosphere, and much of the Earth's volcanism away from hot spots is
attributed to it. The controversy hasn't been decided, but there is growing
evidence in favor of the asthenosphere being the source of magma that fuels
Kilauea, among other volcanoes. If this is the case, then there is a problem.
Hot spots have long been thought by many to be pretty much immobile due their
origin deep in the Earth. Motion of the crust has been measured by its movement
over these hot spots. Some re-evaluation may be necessary if the hot spots
originate close to the Earth's surface.